Electric switch



Patented Nov. 10. 192.5.

UNI TEDSTATES PATENT OFFICE.

CLARENCE T. EVANS, OF MILWAUKEE, \VISCONSIN, ASSIGNOR TO THE CUTLER- HAMMER MFG. CO., OF MILWAUKEE, WISCONSIN, A CORPORATION OF WISCONSIN.

ELECTRIC SWITCH.

Application filed May 26, 1921.

To all who m iii may concern Be it known that I, CLARENCE T. Evan's, a citizen of the United States, residing at Milwaukee, in the county of Milwaukee and State of lVisconsin, have-invented new and useful Improvements in Electric Switches, .of which the following is a full, clear, concise, and exact description. reference being had to the accompanying drawing, forming a aart of this specification.

his invention relates to electric switches and more particularly to switches having associated electro-magnetic means controlled thereby to produce a magnetic field for blowout or other purposes.

While not limited thereto the invention is particularly applicable to switches employmg such electro-magnetic means for blowout purposes and therefore such application of the invention is selected for specific consideration.

lVhere switches are employed for interrupting circuits of high potential, as also in certain other instances, it has been found desirable to-provide the same with a plurality of sets of contacts connected in parallel and the present invention has among its objects to provide such switches with improved electro-magnetic blowout means.

Another object of the invention is to providc such switches with blowout means so designed as to minimize the amount of conducting material required for the coils thereof or in other words so designed as to ob- .5 min a maximum blowout efiect bye'mployment of turns of a given cross section.

Another object is to provide blowout means of the aforesaid character which will be effective to the same degree regardless of the sequence in which the plurality of sets of parallel connected cont-acts disengage.

Another object is to provide a switch of the aforestated character having blowout means tending to equalize the division of 5 current between its several sets of contacts. Various other objects and advantages of the invention will hereinafter appear.

The accompanying drawing illustrates a switch embodying the invention in one form which will now be described, it being understood that the same is susceptible of various modifications and of different uses of the magnetic field controlled thereby without departing from the scope of the appended claim,

Serial No. 472,642.

In the drawing,

Fig. 1 is a front elevational view of the switch; 5

Fig. 2 is a vertical sectional view through the upper portion of the switch shown in Fig. 1; p I

Fig. dis a top plan view of said switch; and I Fig. 4c is a diagrammatic view illustrating the circuit connections of said switch.

Referring to the drawing the switch comprises four movable contacts 1 to 4 carried by the armature member 5 of an electromagnet 6 best shown in Fig. 2. The contacts 1 to t are arranged to respectively engage co-operating stationary contacts 7 to 10 (Fig. 3) said sets of contacts being divided into two parallel connected groups.

The contacts 1 and 2 are respectively connected by leads 11 and 19. to a common binding post 13 while their co-operating contacts 7 and 8 are mounted upon and electrically connected to a common supporting member 14: fixed to an insulating base 15 which also carries electro-magnet 6. The contacts 3 and 4: on the other hand are respectively connected by leads 16 and 17 to a common binding post 18 while their cooperating contacts 9 and 10 are mounted upon and electrically connected to a common supporting member 19 also fixed to the support- 15 and electrically independent of the supporting member 14. It will thus be apparent that the two sets of co-operating contacts 17 and 28 provide a conducting path paralleling the sets of contacts 39 and 4l10 and that the two sets of contacts of each group likewise parallel one another. Also it will be apparent that even if the two groups of contacts are desi ned and adjusted to interrupt circuit substantially simultaneously they will be subjected to such inequalities in wear as to render simultaneous disengagement highly improbable and the sequence of disengagement very uncertain. In other words the contacts of either group may disengage prior to disengagement of the contacts of the other group with the result that the contacts of the latter group are subjected to the full current until they disengage and until the arcs drawn therebetween are interrupted. As best illustrated in Fig. 2 each of the con tact members 1 to 4 is pivotally mounted on the armature member and biased by a spring to a given position on said; member, said spring being compressed upon engagement of said contact with its respective stationary therebetween the contacts 1-7 'and2'-8 and the winding 21 is arranged in series with said contacts. On the. other handthe pole pieces and Qt are arranged to receive therebetween the contacts 3-9 and ir-10 and the coil 22 is connected in series with said contacts. The coils 21' and22jhave their adj acentterminalls connected to a common binding post 26' while their oppositetermina-ls are respectively connected to the contact supporting members 145 and 19'. As illustrated. the coils. are formed of relatively heavy. strips and are respectively provided with tubular core members 27 and 28 threaded. by. abolt 29' upon which the pole pieces 2522a and 25. are mounted.

It will thusbe, apparent from Figv 5v that the currenttraversing.tlie switch divides between the two coils when both. groups of contacts ofsaid' switch are engaged whereas upon disengagement of the, contacts. of either group. the, entire current traverses the coil connected in series withthe other group of contacts thereby increasing the magnetic fieldof the, latter coil. Also it, will be apparentthat'the arrangement of pole pieces. is such that the magneticfield of either coil when subjected to the. full current will. be strengthened and concentrated in. the region of. the contacts connected therewith, thereby providingan effective blowoutfor the contacts. last to disengage. Moreover-the re.- duction in distance between the edectivc poles of the blowout device afiords better.

7 control of'the arcs tobe. extinguished,vi. e.,

by providing for strengthening of the"et'- fective magnetic lines of force. In. this connection it is. alsoto be noted that the blowout coils serve as. resistances in. the. parallel branches. of the. control (circuitand.

thence tend to equalize thedivision of current between the several sets of contacts.

Further it will be apparent that this form. otiblo-wout device has importantstructural advantages itbeing apparent that. the coils may be formed of strips of considerably less cross section than would be required assuming useot a single blowout coil subjected continuously to the full current traversing the switch. In fact assuming use of a single coil to produce a magnetic field effective for all of the contacts, saidcoil would require a number of turns at least equal'to the combinedturns of windings 21 and22' and in order to carry the fullcurrent continuously," it would require a cross section approximately twice that of the coils shown.

The iole )ieces and 25 have a aivotal movement about the bolt 29 as an axis whereby they may be moved awayfrom the stationary contacts to give access there'- to, and preferably said pole pieces are provided with slots 30 whereby they may be readily attached to and removed from the bolt 29. Alsothe pole pieces are provided *ith-insulating plates providing separateinsulating chutes between the pole pieces 23 and 24 and pole pieces 2& and 25.- Each chute comprises parallel insulating plates and and a transversely extending plate 33 supportedby bolts 34 and 35 which pass through allot said plates as well as the pole pieces toprovide a unitary structure. 7

T'Yl'iat I claim as new and desire to secure by Letters Patent is The-combinat'ion with an electric switch having, a plurality of sets of cooperating in the region of its controlling contacts upon; opening of the other of said contacts.

In witness-whereof I- have hereunto subscribed my name.

CLARENCE T. EVANS. 

